Patents Assigned to Kawasaki Kasei Chemicals Ltd.
  • Process for the purification of anthraquinone
    Patent number: 4450111
    Abstract: In a process for purifying crude anthraquinone obtained by the oxidation, by molecular oxygen in an aqueous alkali metal hydroxide solution, of an adduct obtained by the Diels-Alder reaction of butadiene with 1,4-naphthoquinone obtained by a catalytic vapor phase oxidation reaction of naphthalene, an improvement characterized in that said crude anthraquinone is subjected to oxidation treatment in an aqueous medium in the presence of a hypochlorite.
    Type: Grant
    Filed: April 29, 1982
    Date of Patent: May 22, 1984
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Tatsuyoshi Komatsu, Shigeaki Numata, Kazuhiro Maruyama
  • Heat-sensitive recording sheet
    Patent number: 4442176
    Abstract: A heat-sensitive recording sheet having a color-forming layer comprising a colorless or pale-colored chromogenic dyestuff and a hydroxyphthalic acid diester having a melting point of from about 60.degree. to about 120.degree. C.
    Type: Grant
    Filed: August 19, 1983
    Date of Patent: April 10, 1984
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Kazuya Nagaoka, Sigeru Yoshii
  • Process for producing 1,4,4a,9a-tetrahydroanthraquinone compound
    Patent number: 4412954
    Abstract: 1,4,4a,9a-Tetrahydroanthraquinone compounds are produced by Diels-Alder reaction of 1,4-naphthoquinone with a conjugated diolefin in the 1,4,4a,9a-tetrahydroanthraquinone compound as a reaction medium.
    Type: Grant
    Filed: July 14, 1981
    Date of Patent: November 1, 1983
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Tatsuyoshi Komatsu, Kenji Usui
  • Process for producing hydroanthraquinones
    Patent number: 4369140
    Abstract: A hydroanthraquinone is produced from a reaction mixture obtained by the Diels-Alder reaction of naphthoquinone with a conjugated diolefin in an inert organic solvent. The reaction mixture in an inert organic solvent is oxidized with an oxidizing agent to decompose quinhydrone or quinhydrone derivative produced by said Diels-Alder reaction and the crystallized hydroanthraquinones are separated from said inert organic solvent.
    Type: Grant
    Filed: December 9, 1980
    Date of Patent: January 18, 1983
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Tatsuyoshi Komatsu, Kenji Usui, Shigeaki Numata
  • Process for producing highly chlorinated copper phthalocyanine
    Patent number: 4330470
    Abstract: A highly chlorinated copper phthalocyanine is produced by chlorinating a copper phthalocyanine in the presence of a catalyst for chlorination in a solvent by charging chlorine under an elevated pressure. The chlorination is carried out in an inert organic solvent incorporating chlorosulfonic acid and/or pyrosulfuryl chloride at a ratio of 1 to 30 wt. % based on said inert organic solvent which maintain dispersibility of said resulting highly chlorinated copper phthalocyanine.
    Type: Grant
    Filed: December 18, 1980
    Date of Patent: May 18, 1982
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Tomio Segawa, Sakae Kuramoto
  • Process for preventing scale deposition
    Patent number: 4277257
    Abstract: A scale deposition from an aqueous slurry of naphthoquinone and phthalic acid can be prevented by adding fine crystals of phthalic acid to the aqueous slurry of naphthoquinone and phthalic acid collected, which slurry is obtained by contacting a gas resulting from a catalytic gas phase oxidation of naphthalene with water or a mother liquor recycled. The fine crystals of phthalic acid have diameters of less than 100.mu., preferably 10 to 40.mu., and can be in an aqueous slurry of phthalic acid pulverized by a pulverizer.
    Type: Grant
    Filed: November 19, 1979
    Date of Patent: July 7, 1981
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Ryo Matsuura, Katsumi Matsuzaki, Masao Narita
  • Purification of naphthoquinone
    Patent number: 4257851
    Abstract: A crude naphthoquinone produced by an oxidation of naphthalene is purified by a reduced pressure distillation of a crude 1,4-naphthoquinone having an acid content of less than 5 equivalent % calculated as monobasic acid and the crude naphthoquinone is preferably treated by an oxidation of oxidizable impurities.
    Type: Grant
    Filed: March 22, 1979
    Date of Patent: March 24, 1981
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Ryo Matsuura, Kazuaki Sakai, Tuneyasu Sato, Yorinobu Yamada, Kowzo Bandow
  • Process for producing 1,4-dihydroanthraquinone
    Patent number: 4176125
    Abstract: 1,4-Dihydroanthraquinones are produced by oxidizing 1,4,4a,9a-tetrahydroanthraquinone or 1,4-dihydroanthrahydroquinone or an inert substituted derivative thereof with molecular oxygen in an aqueous medium at the reaction temperature of lower than 70.degree. C. under the condition of pH of 8.5 to 12.
    Type: Grant
    Filed: November 17, 1977
    Date of Patent: November 27, 1979
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Ryo Matsuura, Shuichi Nakatani, Yukio Nomiyama, Tadashi Ninomiya
  • Process for producing benzanthrone
    Patent number: 4127595
    Abstract: Benzanthrone is produced by reacting a hydroanthraquinone having 1,4-dihydro ring with acrolein or an acrolein precursor in the presence of a dehydration catalyst.
    Type: Grant
    Filed: October 25, 1977
    Date of Patent: November 28, 1978
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Ryo Matsuura, Shuichi Nakatani, Kazuya Nagaoka, Kouji Kusabe, Mikio Kaseda
  • Process for producing anthrone
    Patent number: 4113749
    Abstract: Anthrone is produced by an intramolecular condensation of hydroanthraquinone such as tetrahydroanthraquinone or dihydroanthrahydroquinone by heating it in the absence of oxygen with or without an inert solvent.
    Type: Grant
    Filed: July 25, 1977
    Date of Patent: September 12, 1978
    Assignee: Kawasaki Kasei Chemicals Ltd.
    Inventors: Ryo Matsuura, Shuichi Nakatani, Kazuya Nagaoka, Katsuhiko Hioki